List of top Physics Questions asked in WBJEE

A Wheatstone bridge has the resistances $10\, \Omega,\, 10\, \Omega, 10\, \Omega$ and $30\, \Omega$ in its four arms. What resistance joined in parallel to the $30\, \Omega$ resistance will bring it to the balanced condition?
What current will flow through the $2\,k\Omega$ resistor in the circuit shown in the figure?
An object placed in front of a concave mirror at a distance of $x \,cm$ from the pole gives a $3$ times magnified real image. If it is moved to a distance of $(x+5)\, cm$, the magnification of the image becomes $2$. The focal length of the mirror is
If the focal length of the eye-piece of a telescope is doubled, its magnifying power $(m)$ will be
A body floats in water with $40\%$ of its volume outside water. When the same body floats in an oil, $60\%$ of its volume remains outside oil. The relative density of oil is
Two cells with the same e.m.f. $E$ and different internal resistances $r_1$ and $r_2$ are connected in series to an external resistance $R$. The value of $R$ so that the potential difference across the first cell be zero is
An ideal gas is compressed isothermally until its pressure is doubled and then allowed to expand adiabatically to regain its original volume ($? = 1.4$ and $2^{-1.4} = 0.38$). The ratio of the final to initial pressure is
The charge on the capacitor of capacitance $C$ shown in the figure below will be
A diver at a depth of $12\, m$ in water $\bigg(\mu = \frac{4}{3}\bigg)$ sees the sky in a cone of semi vertical angle
The magnetic field at the point of intersection of diagonals of a square wire loop of side $L$ carrying a current $I$ is
ln the nuclear reaction $ _7^{14} N + X \rightarrow _6^{14} C + _1^1 H, $ the $X$ will be
An object weights $m_1$, in a liquid of density $d_1$ and that in liquid of density $d_2\,$ is $\, m_2.$ The density $d$ of the object is
If the Earth were to suddenly contract to $\frac{1}{n}$ th of its present radius without any change in its mass, the duration of the new day will be nearly
A plano-concave lens is made of glass of refractive index $1.5$ and the radius of curvature of its curved face is $100 \,cm$. What is the power of the lens?
A particle is moving with a constant speed $v$ in a circle. What is the magnitude of average velocity after half rotation ?
A material has Poisson?s ratio $0.50$. If a uniform rod of it suffers a longitudinal strain of $2 ? 10^{-3}$, then the percentage change in volume is
Four charges equal to $-Q$ are placed at the four corners of a square and a charge $q$ is at its centre. lf the system is in equilibrium, the value of $q$ is
The displacement of a particle at time t is $x$, where $x = t^{4}-kt^{3}$ . If the velocity of the particle at time $t = 2$ is minimum, then
A wire of resistance $R$ is elongated $n$-fold to make a new uniform wire. The resistance of new wire
A stone falls freely from rest and the total distance covered by it in the last second of its motion equals the distance covered by it in the first three seconds of its motion. The stone remains in the air for
In the figure below, the capacitance of each capacitor is $3 \mu F$. The effective capacitance between $A$ and $B$ is :
A body is projected horizontally with a velocity of $u$ $ m/s$ at an angle $ \beta $ with the horizontal. The kinetic energy at the highest point is $( \frac{ 3}{ 4} )^{th}$ of the initial kinetic energy. The value of $ \beta $ is
In a common emitter configuration, a transistor has $\beta = 50$ and input resistance $1\, k\Omega$. If the peak value of a.c. input is $0.01\, V$ then the peak value of collector current is
A body weighs 22.42 g and has a measured volume of 4.7 cc The possible errors in the measurement of mass and volume are 0.01 g and cc. Then the maximum error percentage in the density will be
$n$ identical droplets are charged to $V$ volt each. If they coalesce to form a single drop, then its potential will be